Treating hydrocarbon fluids



A118 27, 194@A H. v. ATwELl.

` I TREATING HYDROCARBON FLUIDS Patented Aug. 27 1940 Umfrao ASTATES PATENT i, ori-lcs TREATING HYDROCARBON FLUIDS Application July 29, 1938, Serial No. 221,885

3 Claims.

This invention relates to the treatment of hydrocarbon fluids.

According to this invention paraillnic naphtha is separated into a light naphtha fraction and a 5 heavy naphtha fraction.- The heavy naphtha fraction is heated and contacted with a catalytic mass to convert constituents of the heavy naphtha fraction into aromatic compounds and during this treatment normally gaseous hydrocarbons t containing olefins are formed. The products of conversion are treated to separate a fraction within the gasoline boiling range which contains aromatic constituents and has a high anti-knock value from normally gaseous hydrocarbons. The

ll normally gaseous hydrocarbons contain considerabie amounts of olens and are preferably combined with gases separated from reaction products resulting from the reforming of the light naphtha fraction and further treated to form 20 higher boiling hydrocarbons as will be presently described.

'Ihe combined gases are treated in any suitable manner to separate C and C4 hydrocarbons, and, if desired, C2 hydrocarbons from gases containing 25 hydrogen and methane. The C3 and C4 hydrocarbons and C2 hydrocarbons are maintained under suitable conditions to polymerize the normally gaseous hydrocarbons and form higher boiling hydrocarbons containing aromatic constituents.

30 The reaction products are separated into a iraction containing aromatic constituents which is in the gasoline boiling'range from vapors which contain normally gaseous hydrocarbons.

The last mentioned normally gaseous hydro-l 35 carbons may be treated to separate C3 and C4 hydrocarbons from gases containing hydrogen and methane and may be recycled to the polymerization zone but they are preferably mixed with the light naphtha fraction and converted o during the reforming of the light naphthafraction. These Ca and C4 hydrocarbons contain a relatively large proportion of parafllnic constituents and are preferably admixed with the light naphtha fraction and recycled to the heating zone for the light naphtha fraction. The light naphtha fraction separated from the charge of parainic naphtha together with the Ca and C4 hydrocarbons is passed through a heating zone wherein it is maintained under superatmospheric 50 pressure and at an elevated temperature to reform the light naphtha constituents. The products of conversion are separated into a fraction within the gasoline boiling range and vapors which contain normally gaseous hydrocarbons 55 which are preferably combined with the normally gaseous hydrocarbons separated from the conversion products leaving the catalytic treatment as above described.

In the drawing there is diagrammatically represented one form of apparatus which may be 5 used to practice the process of my invention.

Referring now to the drawing, the reference character I0 designates a line for conducting the charge of parainic naphtha to be treated. The parainic naphtha may be a straight run gasoline or a similar fraction and it is passed through line I0 by pump I2 toA a still I4 heated in any suitable manner such as a coil I6 to vaporlze lighter constituents therefrom. Instead of still I4 I may use a fractionator and a preheater such as a heat V exchanger or fired coil for heating the charge passing through line IIJ. During the vdistillation .the vapors are fractionated and the paraflinic naphtha is separated into a heavy naphtha fraction which is withdrawn from the bottom of the still I4 through linev I8, and light naphtha vapors which pass overhead through line 20 and are condensed to form a light naphtha fraction.

The heavy naphtha fraction is passed through line I8 by pump 22 and through'a heating zone 25 24 in a heater 26 to raise the temperature of the heavy naphtha fraction and completely vaporlze it. The heavy naphtha vapors are passed through line 28 into the upper portion of a catalyst chamber 30 containing catalytic material 32. 30 'I'he catalytic material 32 may be a chromic oxide catalyst obtained by treating a chromium compound to separate a precipitate in gelatinous form. The heavy naphtha vapors at a temperature of about 900-1050 F. and under substan- -35 tially atmospheric pressure are contacted with theA catalytic material 32 to dehydrogenate the heavy naphtha vapors and to convert them into aromatic compounds. A pressure higher or lower than atmospheric may be used and also the temperature may be varied.

The converted heavy naphtha vapors are withdrawn from the bottom of the catalytic chamber 30 and passed through line 34 to a separating zone 36 to separate llquidresidue from vapors. The 45 liquid residue is withdrawn through line 38 and the vapors leave the top of the separating zone 36 through line lll. The vapors are fractionated Ain fractionating zone or tower 42 to separate a hydrocarbon fraction within the gasoline boiling 50 range from vapors containing normally gaseous hydrocarbons. The hydrocarbon fraction contains aromatic constituents and forms a high anti-knock motor fuel which may be used as such orit may be used as blending stock. u

The remaining vapors contain normally gase- `ous hydrocarbons and leave the upper portion of the fractionating zone 42 through line 46 and are preferably combined with vapors containing normally gaseous hydrocarbons separated from products leaving the heating zone for the light naphtha fraction and further treated as will be presenti:r described. However, normally gaseous hydrocarbons passing through line 46 may be separately treated to separate C3 and C4 hydrocarbons which may be passed to a heating zone later to be described.

The light naphtha vapors leaving the top of the still I4 through line 20 are passed through a condenser 48 to condense a light naphtha fraction containing normally liquid constituents. The normally liquid constituents are passed to a receiver 50 having a valved gas outlet 5|. The liquid hydrocarbons are withdrawn from the bottom of the receiver 50 and passed through line 52 by pump 54 through a heating zone 56 in a heater 58 wherein the light naphtha fraction is heated to about l0501200 F. and maintained under a pressure up to about 500 pounds per square inch to reform the light naphtha constituents. The temperatures and pressures may be varied and are not to be confined to the limits given.

The light naphtha fraction passing through line 52 is preferably admixed with normally gaseous hydrocarbons containing parailnic C3 and C4 hydrocarbons and, if desired, C2 hydrocarbons which are obtained during the latter part of the process as will be hereinafter described in greater detail. The C3 and C4 hydrocarbons and, if desired, C2 hydrocarbons, are converted into higher boiling hydrocarbons during the reforming of the light naphtha constituents.

The reformed light naphtha constituents and converted C3 and C4 hydrocarbons are passed through a pressure reducing valve 60 into a separating or evaporator zone 62 to separate liquid residue from vapors. If desired, a. quench oil may be introduced through line 64'. The liquid residue is withdrawn from the bottom of the evaporator or separating zone 62 through line 66. 'I'he separated vapors leave the upper portion of the separator or evaporating zone G2 through line 68 and are passed to a fractionating zone 10 to separate normally liquid hydrocarbons within the gasoline boiling range from lighter vapors. The normally liquid hydrocarbons are Withdrawn from the bottom of the fractionating zone 10 through line 12 and comprise a hydrocarbon fraction Within the gasoline boiling range having a relatively high anti-knock value and which may be separated as a product or which may be blended with the hydrocarbon fraction containing aromatic constituents formed by the catalytic treatment and which is Withdrawn from the bottom of the fractionating zone 42 through line 44.

The vapors leaving the upper portion of the fractionating zone 10 are passed through line 14 and are preferably combined with vapors-leaving the upper portion of the fractionating zone 42 which` receives the vapors separated from conversion products resulting from the catalytic treatment of the heavy naphtha fraction in catalyst chamber 30. The light vapors contain normally gaseous hydrocarbons and they are treated in any suitable manner to separate C: and C4 hydrocarbons, and, if desired, C2 hydrocarbons, from hydrogen and methane. One way of separating the C3 and C4 hydrocarbons fromv the heavier constituents in the vapor charge are condensed and separated in the fractionating zone or separating zone from lighter vapors. The separating or fractionating zone 80 is provided with a valved gas outlet 82 for removing gases containing hydrogen and methane and also ethane, if desired. The liquefied normally gaseous hydrocarbons containing Ca and C4 hydrocarbons are withdrawn from the bottom of the fractionating or separating zone 80 and are passed through line 84 by pump 88 and through a heating zone 88 in a heater 90.

During passage through the heating zone 88 the liqueiied normally gaseous hydrocarbons are raised to a temperature of about 1100 to 1300 F. while maintained under atmospheric pressure or under a pressure up to about pounds per square inch to effect conversion of the normally gaseous hydrocarbons into higher boiling hydrocarbons suitable for use as a motor fuel. Under the conditions given the nomally gaseous hydrocarbons are polymerizd to form higher boiling hydrocarbons containing aromatic constituents. The reaction products are introduced into a separating zone 94 for separating liquid residue from vapors, the liquid residue being withdrawn from the bottom of the separating zone through line 96, The vapors pass overhead through line 98 and are passed to a fractionating zone or tower |00 to separate normally liquid hydrocarbons from lighter vapors. The normally liquid hydrocarbons contain aromatic constituents and comprise a rproduct Within the gasoline boiling range which is withdrawn through line |02 and may be separated as a product or which may be blended with the gasoline fraction separated from the products of conversion resulting from the treatment in catalytic chamber 30 and passing through line 44 from the bottom portion of the fractionating zone 42. Also the product passing through line |02 may be blended with the reformed naphtha constituents passing through line 12, or all the products passing through lines 44, 12 and |02 may be blended together, if desired.

The lighter vapors separated in the fractionating zone |00 leave the upper portion thereof through line |04 and these vapors are preferably treated in any suitable manner to separate C3 and C4 hydrocarbons from gases containing hydrogen and methane, and, if desired, ethane. One method of effecting this separation is to subject the vapors to pressure by passing them through a compressor |06, cooling the compressed charge by passing it through cooler |08 in order to condense the heavier constituents and passing the compressed and cooled charge to a separating or fractionating zone 0. 'I'he fractionating or separating zone ||0 is provided with a valved gas outlet ||2 for removing gases containing hydrogen and methane. During fractionation in the fractionating or separating zone ||0, liquefied normally gaseous hydrocarbons are separated and are withdrawn from the bottom portion of the fractionating zoneor tower iin through line ||4.

The liqueed normally gaseous hydrocarbons are relatively rich in parailinic hydrocarbons and may contain l0 to 15% olens and Ir'prefer to admix these hydrocarbons with the night naphtha, fraction which is to be passed through heating sone It. A portion or all of the liquefied normally gaseous hydrocarbons is passed through line H4 by pump lli and through line IIB for admixture with the light naphtha fraction passing through line 52 to eiect reforming of the light naphtha vapors and the conversion of Ca and C4 hydrocarbons into higher boiling hydrocarbons.

Instead of thermally polymerizingthe liquefied normally gaseous hydrocarbonsV in heating zone Il, I may catalytically polymerize them in which event the liqueied normally gaseous hydrocarbons passing through line IM will contain about 5% olefins.

Ii desired, all or a portion of the separated Ca and C4 hydrocarbons may be passed through line I2. and recycled through the heating or polymerization zone 88 for further treatment therein, instead of being recycled to the naphtha reforming zone 5I. The material charged to any of the stages in my process may be supplemented by similar material from any suitable outside source.

While I have shown one form of apparatus and have given an example with specinc operating conditions in connection therewith, it is to be expressly understood that I am not to be restricted thereto as other apparatus or other arrangements and different operating conditions may be used, and different operating conditions may be used with diierent charging stocks'without departing from the spirit of my invention.

I claim: y

1. A process of treating hydrocarbons to produce motor fuels which comprises separating a parafllnic naphtha fraction into a relatively heavy naphtha fraction and a relatively light naphtha fraction, heating the heavy naphthafraction and passing the heated heavy naphtha vapors in contact with a catalyst to -dehydrogenat'e certain of l the naphtha constituents and convert them into aromatic compounds, fractionating the converted y vapors to separate a fraction within the gasoline boiling range and containing aromatic constituents from normally gaseous hydrocarbons, heating the relatively light naphtha fraction and passing the light naphtha vapors through a conversion zone wherein they are maintained under superatmospheric pressure and at an elevated temperature to effect the desired extent of conversion, fractionating the resulting vapors to separate a fraction within the gasoline boiling range from normally gaseous hydrocarbons, treating the normally gaseous hydrocarbons obtained during the two fractionating steps to separate C: and C4 hydrocarbons, heating the separated C: and C4 hydrocarbons to convert them into higher boiling hydrocarbons, and separating the converted products into vapors and liquid residue. fractionating the last mentioned vapors to separate a fraction boiling within the gasoline boiling range from normally gaseous hydrocarbons, separating C: and C4 hydrocarbons from the last mentioned normally gaseous hydrocarbons and i recycling at least a portion thereof to said conrange from normally gaseous hydrocarbons, treating the normally gaseous hydrocarbons obtained during the fraotionating steps to separate C3 and- C4 hydrocarbons, heating the separated' C; and C4 hydrocarbons in a polymerization zone to convert them into higher boiling hydrocarbons and separating the converted products into vapors and liquid residue, fractionating the last mentioned vapors to separate a fraction boiling within the gasoline boiling range from normally gasecus hydrocarbons, separating C: and C4 hydroeous hydrocarbons and recycling at least a portion thereof to said conversion zone for admixture with the relatively light naphtha traction to oonvert them into higher boiling hydrocarbons during the conversion of the light naphtha vapors, and recycling another portion of the last mentioned C3 and C4 hydrocarbons to said polymerization zone for further treatment.

lcarbons from the last mentioned normally gas- "z5 3. A process for treating a naphtha of relatively low anti-knock value to effect conversion thereof to gasoline motor fuel of high anti-knock value which comprises fractionating` said naphtha into a light naphtha fraction and a heavy naphtha fraction, heating said light naphtha fraction under reforming conditions to temperature and pressure to eflect substantial conversion thereof`` to gasoline constituents of improved anti-knock value, fractionating the products of said reforming treatment lto separate a fraction within the gasoline boiling range, separately contacting the heavy naphtha4 fraction with a dehydrogenating catalyst at elevated temperature for a time sum- `cient to effect the substantial production ot aromatic hydrocarbons therein by dehydrogenatlon and cyclization reactions, fractionating the products of said dehydrogenation treatment to sep,- arate a fraction boiling within the gasoline boiling range and containing aromatic constituents, treating normally gaseous hydrocarbons obtained during said conversion treatments to separate therefrom a normally gaseous fraction consisting of normally gaseous hydrocarbons containing at least two carbon atoms per molecule, subjecting said normally gaseous fraction to polymerizing conditions to effect substantial conversion thereof to normally liquid hydrocarbons boiling within the gasoline boiling range, fractionating the products of said gas conversion treatment to separate therefrom a fraction boiling within the gasoline boiling range and a normally gaseous fraction consisting of normally gaseous hydrocarbons containing at least two carbon atoms per molecule, and recycling at least a portion of said last-mentioned normally gaseous traction for admixture with the said light naphtha fraction undergoing reforming treatment whereby said normally gaseous hydrocarbons undergol thermal conversion treatment during said naphtha reforming treatment.

HAROLD V. ATWm-L. 

